Mr Rahman is now under protection at a secret location in Italy, the interior ministry has said.

There had been an international outcry at the prospect of the Christian convert being executed for his religious beliefs.

The Pope wrote to Afghan President Hamid Karzai last week, saying that dropping the case "would bestow great honour upon the Afghan people and would raise a chorus of admiration in the international community".

Denounced by relatives

Politicians in Afghanistan opposed Mr Rahman's release from trial as "contrary to the laws in place in Afghanistan", and condemned Western "interference" on his behalf.

The case has highlighted ambiguities in Afghanistan's constitution over the interpretation of religious issues.

Mr Rahman, who converted 16 years ago while working as an aid worker for an international Christian group, was arrested after police discovered him with a Bible.

An ethnic Tajik originally from the Panjshir Valley, north of Kabul, Mr Rahman returned to Afghanistan a few years ago.

It is thought that he was denounced by relatives after returning to seek custody of his two daughters.